The present invention relates to a substrate treating apparatus for subjecting a substrate, such as an LCD substrate or semiconductor wafer, to a thermal treatment, such as a heating treatment, cooling treatment, or hydrophobic treatment, in a system for subjecting the substrate to, for example, coating of a resist liquid, and development of a resist film.
In a process of manufacturing, for example, LCDs or semiconductor devices, electric circuits are formed by means of a so-called lithography technique, in which an object to be processed, i.e., a substrate is coated with a photoresist, and then the photoresist is light-exposed in accordance with a circuit pattern and is developed.
Such resist coating and developing steps include heating treatments and cooling treatments thereafter, to perform a pre-baking treatment for stabilizing the resist, a post-exposure-baking treatment after the light-exposure, and a post-baking treatment after the development. These heating treatments and cooling treatments are respectively carried out in heating treatment apparatuses each having a heating plate and cooling treatment apparatuses each having a cooling plate. Further, in a hydrophobic treatment using HMDS, the substrate is heated by a heating plate similar to that used in the heating treatment apparatuses.
As shown in FIG. 1, such a heating, cooling, or hydrophobic treatment apparatus has a plate 101 for heating or cooling a substrate S, a plurality of lifter pins 103 inserted in holes 102 formed in the plate 101, and a support member 104 supporting the lifter pins 103. The support member 104 is moved up and down by an elevating mechanism (not shown) so that the lifter pins 103 are moved up and down by the support member 104, when the substrate S is transferred between a transfer position and a process position.
In the heating treatment apparatus, however, when the temperature of the plate 101 is increased to heat the substrate S, the pitch of the holes 102 is shifted due to thermal expansion of the plate 101. Similarly, in the cooling treatment apparatus, the pitch of the holes 102 is shifted due to thermal contraction of the plate 101.
Conventionally, in order to accommodate the structure to the shift in the pitch of the holes caused due to thermal expansion or contraction of the plate 101, the holes 102 are formed to have a larger diameter to widen a gap around the pin 103 in each hole 102. In other words, the gap around the pin 103 in each hole 102 has a size large enough to allow the pin 103 to be moved up and down without a hitch even when the pitch of the holes 102 are shifted.
However, since the substrate S is not heated or cooled at portions where the holes 102 have such a large diameter, the temperature distribution on the substrate S becomes less uniform.
In order to solve this problem, Jpn. Pat. Appln. KOKAI Publication No. 8-313855 discloses a technique. In this technique, lifter pins 103 are provided with play at portions where the lifter pins 103 are attached to a support member 104, so that the pins 103 can move to follow a shift in a hole pitch. With this arrangement, since the holes do not have to have a larger diameter, the temperature distribution on a substrate S is prevented from becoming less uniform.
However, in this technique, since the lifter pins do not swiftly follow the shift in the hole pitch, the pins are apt to be inclined. Besides, the pins require some rigidity, and thus should not be too thin. Accordingly, the diameter of the holes cannot be so small, thereby bringing about a limit in increasing uniformity in the temperature of the substrate with a high accuracy.